Tony Randall, who enjoyed more than six decades as a radio, stage, screen, and TV actor but was best remembered for his five-year stint as the fussy Felix Unger opposite Jack Klugman’s slovenly Oscar Madison on the 1970s ABC sitcom ”The Odd Couple,” died Monday night in his sleep at New York’s NYU Medical Center, his publicist said in a statement. The 84-year-old, hospitalized since undergoing heart surgery in December, died from ”complications from a prolonged illness,” the publicist said.

Born Leonard Rosenberg in Tulsa in 1920, Randall made his Broadway debut in 1941. (Fifty years later, he would found the National Actors Theater, a company whose mission was to perform classic plays on Broadway.) In his early career, Randall earned fame in best friend roles, opposite Wally Cox on TV’s ”Mr. Peepers” in the early 1950s, and in several memorable movies opposite Rock Hudson and Doris Day at the turn of the 1960s (”Pillow Talk,” ”Send Me No Flowers,” and ”Lover Come Back”), where he played the effete foil to romantic leading man Hudson.

A decade later, Randall would perfect his metrosexual persona with his role as Felix Unger during the 1970-75 ”Odd Couple,” making indelibly his own a character that had been played by two prominent stars before him, Art Carney (on Broadway) and Jack Lemmon (on film). The role won Randall an Emmy in 1975. From 1981 to 1983, he starred on another sitcom, ”Love, Sidney,” as a character who was more explicitly gay, a decade and a half before ”Ellen” and ”Will & Grace” made gay lead sitcom characters common.

Always, Randall seemed to be playing the urbane intellectual, a role that made him a favorite raconteur on late-night talk shows, where he appeared several hundred times opposite Johnny Carson, David Letterman, and Conan O’Brien. In later years, Randall did things that belied his image, like appearing covered in mud on Letterman’s ”Late Show,” or starting a family in his late 70s. (Three years after Florence, his wife of 54 years, died in 1992, Randall married Heather Harlan, an NAT actress 50 years his junior, who bore him the first of his two children when he was 77.) Still, Randall couldn’t escape from Felix’s shadow. In 1993, when a hapless EW interviewer asked him if he was at all like the persnickety Felix, Randall said, ”I’ve been asked that same stupid question in every single interview I’ve done since 1970 – that’s about 25,000 interviews.” And the answer? ”No. I’m nothing like Felix at all.”